A control device of the pre-cited type is known from U.S. Pat. No. 5,483,930. Through an adequate positioning of the valve control piston of the control valve in a hold position by a control circuit it is assured that one of the chambers of the adjusting element of the control device is supplied with an additional quantity of hydraulic fluid for compensating fluid leakage and stabilizing the position of the adjusting piston of the adjusting element.